For at least a century not a year has passed in which British soldiers have not been off fighting somewhere in the world. Churchill's "rattle of musketry" reverberates down the decades. From the wars of late empire to the conflicts with Germany and Japan, the brush wars of the cold war period, and the interventions and expeditions of the era now passing, our armed forces have been almost continuously deployed.

Our survey of this long and bloody history may startle some who believe that the British resort to force only in exceptional circumstances, and only in self-defence. In fact, we do it all the time, as recent histories of imperial wars have demonstrated in often chilling detail. Could all this be about to stop? Our writers suggest that a combination of war-weariness, the diminished effectiveness of our forces after yet another round of spending cuts, the failures that marked the Iraq and Afghanistan wars, and the difficulty of building popular support in a society that now has substantial minorities hailing from the potential battle zones, mean that 2015 could be the first year with no British shots fired in anger. Officers call this "a strategic pause". Certainly, the prospect of it should prompt discussion about the purposes of our armed forces.

The nations of Europe spend close to €200bn annually on defence and keep one and a half million men and women under arms, with another four million in reserve, and paramilitary forces. What are they for? They are not for colonial control. They are not (after the end of the cold war) for defence against the Warsaw Pact. They are not (after Afghanistan, Iraq and Libya, and in spite of Mali and the Central African Republic) for major interventions outside Europe whether in conjunction with the Americans or separately.

They are not (given the nature of asymmetrical conflict) for fighting "terrorism". Intelligence-led operations and, very arguably, drones are the preferred choice of our governments for that problematic task.

They are not (we must hope, and after partial settlements in Ireland, Spain, Corsica and the former Yugoslavia) for suppressing European rebels and separatists. They are no longer (with the end of conscription in most European countries) a means of consolidating national unity through an obligation of military service binding on all (at least on all males).

They are clearly of value in border control, maritime patrol, fisheries protection, piracy patrol, anti-smuggling measures, as general-purpose forces in emergencies such as major floods, fires, earthquakes, or nuclear accidents, and as providers of contingents for UN peacekeeping operations, including technical back-up for less well-equipped troop donors.

Yet are these useful functions best met by forces that have been expensively trained for combat against other sophisticated armies or for use in insurgencies? Arguably, many of their skills are redundant and much of their equipment irrelevant. That goes especially for British and French nuclear weapons.

Soldiers will say that armies are insurance companies, and military spending is the premium. Might Europe in the future once again have enemies akin to the old Soviet Union? Russia itself? Iran? China? Even if that could happen, how relevant would tank and infantry armies be? Again, could there be a new era of intervention in which, because of the compelling nature of the situation, Britain and other European nations, with or without the Americans, would need to send large forces abroad? Say, total breakdown in Syria with weapons of mass destruction out of state control?

Is the 21st century, in general, so unpredictably dangerous that we need to maintain state of the art militaries on the basis that if we let the skills, traditions and supporting industries die it will be impossible to revive them? Or do we need to start thinking about our military establishment less in terms of firepower and more in terms of a fire brigade, with war somewhere in the middle, rather than right at the top, of the list of duties?